Packet classification based power saving receiver

ABSTRACT

Receivers, apparatuses, and methods associated with packet classification based power saving receiver are described. In one embodiment, a method includes detecting an incoming frame at a receive unit. Expected power savings are calculated based, at least in part, on a switching time and frame duration of the incoming frame. The method further includes determining to enter an ignore frame state rather than a receive frame state based, at least in part, on the expected power savings. In the receive frame state the incoming frame is received by the receive unit. In the ignore frame state the incoming frame is either not received or not decoded. The method also includes selectively controlling the receive unit to enter the ignore frame state from the receive frame state. The receive unit is returned to the receive frame state in time to perform end of frame processing on the incoming frame.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent disclosure is a continuation of U.S. patent application Ser.No. 12/951,518 filed on Nov. 22, 2010, now U.S. Pat. No. 8,755,315;which claims the benefit of U.S. provisional application Ser. No.61/292,419 filed on Jan. 5, 2010, the disclosures of which are whollyincorporated herein by reference.

BACKGROUND

Conventional 802.11 wireless receivers typically include, among otherunits, a radio frequency unit (RFU), an analog baseband processing (ABB)unit, a digital baseband processing (DBB) unit, and a media accesscontrol (MAC) unit. Such conventional 802.11 wireless receiverstypically receive and decode all frames detected by the wirelessreceivers. For example, after being decoded, frames intended for a hostare provided to the host, while frames not intended for the host arediscarded or ignored. Unfortunately, receiving and decoding frames thatare not intended for a host wastes power.

A classification/filtering scheme is generally used to determinedwhether or not frames are intended for a host. Classification is aprocess of extracting information from the MAC Header and signal fieldof an incoming frame—e.g., a MAC address of the receiver (targetaddress), a MAC address of the sender, a frame type, a subtype, andQOS—and assessing the information with a set of policies as defined by ahost, which results in classification of the frame as being intended ornot intended (filtered) for the host.

Information required for classification of a frame is typicallyavailable in a relatively small portion at the beginning of the frame,thus providing ample opportunity to save power by switching the receiversubsystems to low power states for the remaining duration of a framedetermined to be filtered out.

Conventionally, if a filtered frame is received correctly (e.g., framecheck sequence (FCS) pass, cyclic redundancy check (CRC) pass), then theduration-id field in the incoming frame is used as a virtual carriersense, and network allocation vector (NAV) processing is triggered forthe end of frame processing associated with a carrier sense multipleaccess with collision avoidance (CSMA/CA) protocol. Additionally, if afiltered frame is received incorrectly (e.g., FCS fail, CRC fail), thenextended inter-frame spacing (EIFS) is triggered for the end of frameprocessing for the CSMA/CA protocol.

SUMMARY

In one embodiment, a method includes detecting an incoming frame at areceive unit. Expected power savings are calculated based, at least inpart, on a switching time and frame duration of the incoming frame. Themethod further includes determining to enter an ignore frame staterather than a receive frame state based, at least in part, on theexpected power savings. In the receive frame state the incoming frame isreceived by the receive unit. In the ignore frame state the incomingframe is either not received or not decoded. The method also includesselectively controlling the receive unit to enter the ignore frame statefrom the receive frame state. The receive unit is returned to thereceive frame state in time to perform end of frame processing on theincoming frame.

In another embodiment, a receiver apparatus includes a receive unit anda controller. The receive unit is configured with a receive frame stateand an ignore state. In the receive frame state, the receive unit isconfigured to receive an incoming frame and to provide decodedinformation concerning the incoming frame. In the ignore frame state,the receive unit is configured to perform not receiving the incomingframe or not decoding the incoming frame. The controller is configuredto calculate expected power savings based, at least in part, on aswitching time and frame duration of the incoming frame. The controlleris also configured to determine to enter an ignore frame state ratherthan a receive frame state based, at least in part, on the expectedpower savings. The controller is further configured to selectivelycontrol the receive unit to enter the ignore frame state from thereceive frame state and return the receive unit to the receive framestate in time to perform end of frame processing on the incoming frame.

In another embodiment, a method for controlling power modes for one ormore sub-systems in an 802.11 receiver is described. The method includesdetecting an incoming frame being received at the receiver via awireless signal. The method further includes controlling the receiver toreceive and decode the incoming frame until frame information comprisingan intended target for the incoming frame and a frame duration for theincoming frame have been acquired. The method also includes selectivelycontrolling one or more sub-systems in the receiver to change state froma higher power receive mode to a lower power save mode as a function ofthe frame information and an expected power savings. The expected powersavings is computed as a function of the frame duration and switchingtimes for the one or more sub-systems. The method includes selectivelycontrolling one or more sub-systems in the receiver to change state fromthe lower power save mode to the higher power receive mode in time tomaintain end of frame processing associated with a carrier sensemultiple access collision avoidance (CSMA/CA) protocol with which the802.11 receiver is complying and in time to detect the next incomingframe.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate various receivers, apparatuses,methods, and other embodiments. It will be appreciated that theillustrated element boundaries (e.g., boxes, groups of boxes, or othershapes) in the figures represent one example of the boundaries. In someexamples one element may be designed as multiple elements or multipleelements may be designed as one element. In some examples, an elementshown as an internal component of another element may be implemented asan external component and vice versa. Furthermore, elements may not bedrawn to scale.

FIG. 1 illustrates one embodiment of a packet that can be input to apacket classification based power saving receiver.

FIG. 2 illustrates one embodiment of a packet classification based powersaving receiver.

FIG. 3 illustrates another embodiment of a packet classification basedpower saving receiver.

FIG. 4 illustrates one embodiment of a method associated with a packetclassification based power saving receiver.

FIG. 5 illustrates more details concerning portions of a methodassociated with a packet classification based power saving receiver.

DETAILED DESCRIPTION

Example receivers can save power when compared to conventional receiversby selectively reducing power in one or more receiver subsystems upondetermining that an incoming frame is to be ignored. The determinationto ignore a frame may be based on information contained in header fields(e.g., MAC HEADER fields) appearing in an incoming frame. Theinformation may reveal, for example, that the incoming frame is notintended for a host associated with the receiver's MAC unit. Thedetermination may also be based on the strength of the signal associatedwith the incoming frame and/or a signal-to-noise ratio (SNR) associatedwith the signal. The header fields may identify the frame intendedtarget. The header fields may also provide information from which theremaining time required to receive the remaining portion of the incomingframe can be determined. The information may be located, for example, ina signal field. A receiver subsystem may be switched to a lower powerstate and then switched back to a power state suitable for receiving thenext incoming frame if the switching can be achieved in an appropriateamount of time given the time it will take to receive the remainingportion of the incoming frame. If there is insufficient time to switchfrom a current power state to a lower power state and then back to areceiving power state, then the incoming frame may be treatedconventionally.

If a receiver subsystem is switched to a lower power state, then thereceiver may perform protocol preserving actions involving the clearchannel assessment (CCA) line and end of frame processing (e.g., NAVupdate, EIFS processing). Since example receivers are selectivelypowered down, they do not continuously sense and decode. Therefore, anexample MAC drives an appropriate state (BUSY) onto the CCA line for theestimated remaining duration of an aborted frame, or until the regularCCA line drive is powered back up. Additionally, an example MAC providesdifferent ways to control either NAV update or EIFS processing at theestimated end of the aborted frame. In one example, the MAC will causeall aborted frames to be treated as FCS fail frames and trigger EIFS. Inanother example, the MAC will cause all aborted frames to be treated asFCS pass frames and trigger NAV update. In another example, the MAC willtreat aborted frames that are longer than a threshold length as FCS failframes and trigger EIFS while treating aborted frames that are shorterthan the threshold length as FCS pass frames and trigger NAV update. TheNAV/EIFS decision may be based on other or additional criteria.

FIG. 1 illustrates one embodiment of an incoming frame (e.g., packet100) that can be input to a packet classification based power savingreceiver. Packet 100 includes a PHY header 110, a signal field 120, aMAC header 130, a payload 140, and a frame check sequence (FCS) 150. ThePHY header 110, the signal field 120, and the MAC header 130 may occupya relative small number of bytes (e.g., 50 bytes) as compared to thepayload 140 which may occupy a relative larger number of bytes (e.g., upto 64 KB). A conventional receiver will still receive and decode theentire payload 140 even if the conventional receiver knows that thepayload 140 is going to be discarded. An example receiver can make aninformed decision about not receiving the payload 140 based oninformation in the PHY header 110, the signal field 120, and the MACheader 130.

In one example, the signal field 120 may include information about theremainder of the packet 100 starting from the end of the signal field120 to the end of the FCS 150. In another example, the signal field 120may include information about the packet 100 as a whole. Given theinformation in the signal field 120 and knowledge about the receiverproperties of a receiver that is receiving packet 100, an estimate canbe made concerning how long it will take to receive the remainder ofpacket 100. Thus, if switching times allow, packet 100 may be ignored byswitching one or more elements in the receiver to a lower power mode.Being able to selectively power down an element(s) in a receiverfacilitates producing a packet classification based power savingreceiver that will consume less power than a conventional receiver.

FIG. 2 illustrates one embodiment of an 802.11 receiver apparatus 200.The apparatus 200 includes a receive unit 210 and a control unit 220.The receive unit 210 and the control unit 220 are configured to receivean incoming frame 230 using a wireless carrier sense multiple accesscollision avoid (CSMA/CA) protocol. In one example, the incoming frame230 may include a physical layer (PHY) header, a signal field, a mediaaccess control (MAC) header, a payload, and a frame check sequence(FCS). The signal field includes information from which the amount oftime expected to be required to receive the remainder of the incomingframe 230 can be computed.

The receive unit 210 can be configured to be in either a receive framestate or an ignore frame state. The receive frame state is a higherpower state than the ignore frame state. The receive unit 210 isconfigured to operate differently when it is in the receive frame statethan when it is in the ignore frame state. When the receive unit 210 isin the receive frame state, the receive unit 210 controls the receiver200 to receive radio frequency (RF) signals associated with the incomingframe 230. When the receive unit 210 is in the receive frame state, thereceive unit 210 also controls the receiver 200 to provide decodedinformation concerning the incoming frame 230. The decoded informationmay be provided, for example, to a host that is using the receiver 200to communicate wirelessly.

When in the ignore frame state, the receive unit 210 is configured tocontrol the receiver 200 to either not receive RF signals associatedwith the incoming frame 230 or to not decode RF signals associated withthe incoming frame 230. Not receiving RF signals can be accomplished bypowering down units in the receiver 200 like antennas and RF receiveelements. Not decoding a received RF signal can also be accomplished bypowering down units like baseband decoders in the receiver 200.

The control unit 220 is configured to selectively control whether thereceive unit 210 is in the receive frame state or the ignore framestate. The control unit 220 can make the decision concerning the receiveunit 210 power state based on different inputs. In one example, thecontrol unit 220 is configured to selectively control the receive unit210 to enter the ignore frame state upon determining that the incomingframe 230 is to be filtered. “Filtering” the incoming frame 230 canrefer, for example, to ignoring, partially ignoring, discarding, and/orpartially discarding the frame. If the control unit 220 causes thereceive unit 210 to enter the lower power state where RF signals are notreceived and/or not decoded, then control unit 220 is also responsiblefor causing the receive unit 210 to return to the receive frame state intime to receive a subsequent incoming frame and in time to perform endof frame processing consistent with the CSMA/CA protocol. Otherwise thereceiver 200 could be a very obtrusive and annoying member of a wirelessnetwork with which it is interacting.

The inputs to the control unit 220 can include information decoded fromthe incoming frame 230. In one example, the information may be locatednear the beginning of the frame to facilitate ignoring a useful amountof following information in the frame 230. The decoded information caninclude, for example, an identifier of an intended target for theincoming frame 230 and an expected duration of the incoming frame 230.In one example, the control unit 220 can determine that the incomingframe 230 is to be filtered (e.g., ignored) based on the intended targetfor the incoming frame 230. If the incoming frame 230 is not intendedfor a host connected to receiver 200, then the incoming frame 230 may bea candidate for filtering. However, just knowing the intended target maynot provide enough information to make a decision to power down anelement(s) in the receiver 200. For example, it may not make sense tobase power down decisions on information received over very weakchannels. Therefore, in one example, the control unit 220 is configuredto determine that the incoming frame 230 is to be filtered based onadditional criteria including, but not limited to, a signal strengthassociated with the RF signals associated with the incoming frame 230,and a signal to noise ratio (SNR) associated with the RF signalsassociated with the incoming frame 230. In this way, the receiver 200will not be powered down due to information carried on a weak channeland thus the receiver 200 will still be able to hear information carriedon stronger channels that may supersede the weak signal.

In one example, the control unit 220 is configured to control thereceive unit 210 to enter the ignore frame state upon determining thatthe incoming frame 230 is to be filtered and upon determining that adesired ratio between switching time and the amount of time expected tobe required to receive the remainder of the incoming frame 230 exceeds athreshold. The switching time comprises the time it takes to switch thereceive unit 210 to the ignore frame state from the receive frame stateand the time it takes to switch the receive unit 210 back to the receiveframe state from the ignore frame state. This additional criteria isevaluated to make sure that it makes sense to power down an element inthe receiver 200 and then to power it back up. Powering down a physicaldevice and then powering up a physical device may not be aninstantaneous operation. For example, it may take time for a capacitorto discharge or for a capacitor to be charged. Additionally, it may taketime for a circuit like a phase-locked loop to stabilize. Therefore, itmay only make sense to power down and power up if the switching timesare less than the duration of the remainder of the incoming frame 230.If the switching times exceed the duration of the remainder of theincoming frame 230, then the receiver 200 may not be ready to performappropriate end of frame processing and may not be ready to hear thenext incoming frame.

The receiver 200 may not be operating alone. Indeed, the receiver 200may be operating as part of a wireless network. To be a good citizen onthe network, and to adhere to a protocol (e.g., CSMA/CA), certainactions may need to be taken when the end of a frame is detected. Theactions may include, for example, signaling whether the frame wasreceived correctly, establishing times for media contention, and so on.Thus, in one example, the control unit 220 controls the receive unit 210to perform end of frame processing consistent with the CSMA/CA protocol.This end of frame processing can include, for example, triggering anetwork allocation vector (NAV) update, and/or triggering extendedinter-frame spacing (EIFS) processing. Since the receiver 200 may nothave received the entire payload of a message that is aborted to savepower, it may be impossible for the receiver 200 to know whether themessage was received correctly. Therefore, in different examples, thereceive unit 210 can be configured to perform different end of frameprocessing consistent with the CSMA/CA protocol. The differenttreatments include, but are not limited to, treating a filtered incomingframe as a frame that has passed a frame check sequence (FCS) test andtherefore triggering NAV update processing for the filtered incomingframe, treating a filtered incoming frame as a frame that has failed anFCS test and therefore triggering EIFS processing for the filteredincoming frame, and selectively triggering NAV update processing when afiltered incoming frame is less than a threshold duration andselectively triggering EIFS processing for a filtered incoming framewhen a filtered incoming frame is longer than the threshold duration.While frame length is described as one criteria for selecting betweenNAV/EIFS processing, other criteria may also be consulted including butnot limited to channel quality and/or bit error rates.

In one example, the receiver 200 may be part of an 802.11 transceiverdevice. The transceiver may include the receiver 200 and a transmitter.The receiver 200 is configured to selectively enter a low power statewhere the remainder of incoming RF signals associated with an incomingframe 230 are not received or decoded upon deciding to ignore theincoming frame 230. The decision to ignore the incoming frame 230 can bemade by the receiver 200 as a function of analyzing information gatheredby partially receiving and partially decoding the incoming frame 230.The information decoded from the incoming frame can include an intendedtarget for the incoming frame 230 and an expected amount of timerequired to receive the incoming frame 230.

FIG. 3 illustrates another embodiment of a packet classification basedpower saving receiver 300. This embodiment of receiver 300 includes ahost interface 310, a MAC unit 320, a digital baseband processing unit(DBB) 330, an analog baseband processing unit (ABB) 340, and a radiofrequency unit (RFU) 350. The MAC unit 320 may include filter logic 322,clear channel assessment logic 324, and NAV/EIFS logic 326. In oneembodiment, the MAC unit 320 may implement the control unit 220 (FIG. 2)while the RFU 350, ABB 340, and DBB 330 may implement the receive unit210 (FIG. 2). The MAC unit 320 can control the overall state of thereceive components by controlling the state of one or more of, the RFU350, the ABB 340, and the DBB 330.

In one example, the RFU 350 is configured to receive the RF signalsassociated with the incoming frame and has two or more power states. TheABB 340 is configured to convert analog baseband signals associated withthe incoming frame into digital baseband signals associated with theincoming frame. The ABB 340 also has two or more power states. The DBB330 is configured to decode the digital baseband signals and to providethe decoded information to, for example, the MAC unit 320. The DBB 330also has two or more power states.

In one example, the two or more power states for the RFU 350 include apower down state where the RFU 350 consumes I_(rf) _(—) _(pd) mA ofpower, a sleep state where the RFU 350 consumes less than I_(rf) _(—)_(slp) mA of power, a standby state where the RFU 350 consumes less thanI_(rf) _(—) _(sb) mA of power, and a receive state where the RFU 350consumes more than I_(rf) _(—) _(rx) mA of power. Where I_(rf) _(—)_(rx)>I_(rf) _(—) _(sb)>I_(rf) _(—) _(slp)>I_(rf) _(—) _(pd). Adifferent number of states may be employed. Similarly, different powerconsumption levels may be associated with different states. In oneexample, the MAC unit 320 may control the RFU 350 power statesindependently of the power states of either the ABB 340 or the DBB 330.

In another example, the two or more power states for ABB 340 include asleep state where the ABB 340 consumes less than I_(ab) _(—) _(slp) mAof power, a standby state where the ABB 340 consumes less than I_(ab)_(—) _(sb) mA of power, and a receive state where the ABB 340 consumesmore than I_(ab) _(—) _(rx) mA of power. Where I_(ab) _(—) _(rx)>I_(ab)_(—) _(sb)>I_(ab) _(—) _(slp). A different number of states may beemployed. Similarly, different power consumption levels may beassociated with different states. In one example, the MAC unit 320 maycontrol the ABB 340 power states independently of the power states ofeither the RFU 350 or the DBB 330.

In another example, the two or more power states for the DBB 330 includea sleep state where the DBB 330 consumes I_(db) _(—) _(sip) mA of power,a standby state where the DBB 330 consumes less than I_(db) _(—) _(sb)mA of power, an idle receive state where the DBB 330 consumes less thanI_(db) _(—) _(idle) mA of power, and an active receive state where theDBB 330 consumes more than I_(db) _(—) _(act) mA of power. Where I_(db)_(—) _(act)>I_(db) _(—) _(idle)>I_(db) _(—) _(sb)>I_(db) _(—) _(slp). Adifferent number of states may be employed. Similarly, different powerconsumption levels may be associated with different states. In oneexample, the MAC unit 320 can control the DBB 330 power statesindependently from the power states of the ABB 340 or the RFU 350.

The MAC unit 320 may be configured to decode frame information from thedecoded information provided by the DBB 330. Recall that an incomingframe may include a physical layer (PHY) header, a signal field, a MACheader, a payload, and a frame check sequence (FCS). Recall also thatthe signal field may include information from which the amount of timeexpected to be required to receive the remainder of the incoming frameis computed.

The MAC unit 320 may include filter logic 322 for determining whether tofilter a frame. The filter decision may be made on criteria includingintended target, sender identity, frame type/subtype, switching timeversus remaining duration time, signal strength, and so on. The MAC unit320 may also include CCA logic 324 for driving a pre-determined signalonto a clear channel assessment (CCA) line controlled by the receiverapparatus while the receive components are in an ignore frame state. Thepre-determined signal may be, for example, a BUSY signal specified bythe 802.11 standard. The MAC unit 320 may also include NAV/EIFS logic326 for selecting and performing either NAV or EIFS processing at theestimated end of the aborted frame. Different NAV/EIFS decisions may bemade based, for example, on packet length or on other criteria.

FIG. 4 illustrates one embodiment of a method 400 associated with apacket classification based power saving receiver. Method 400facilitates controlling power modes in an 802.11 receiver. At 410,method 400 includes detecting an incoming frame being received at thereceiver via a wireless signal. The detecting may be performed by, forexample, an RFU, or a baseband processing unit.

At 420, method 400 includes controlling the receiver to receive anddecode the incoming frame. The receiving and decoding at 420 continuesuntil frame information comprising an intended target for the incomingframe and a frame duration for the incoming frame have been acquired.The intended target may be located, for example, in a MAC header. Theduration may be located, for example, in a signal field. The intendedtarget and duration may provide enough information for making areceive/ignore decision. Since the information may be acquired in arelatively small number of bytes (e.g., 50 bytes) as compared to anoverall frame size (e.g., 64 KB), significant power savings may beachieved if the receiver can be powered down for the remainder of the(64 KB-50) bytes.

At 430, method 400 includes making a determination concerning enteringthe power save mode. If the decision at 430 is no, then a frame may beprocessed using normal operation at 440. If the decision at 430 is yes,then at 450 method 400 may control a receiver to enter power save mode.Entering power save mode at 450 may include controlling a sub-system(s)(e.g., RFU, ABB, DBB) in the receiver to change state from a higherpower receive mode to a lower power save mode. One or more of the RFU,ABB, and DBB may be controlled. The determination at 430 may be made asa function of the frame information and an expected power savings. Theexpected power savings may be computed, for example, as a function ofthe remaining frame duration and switching times for the sub-system(s)to be powered down and powered up back. For example, if the time toswitch a sub-system(s) into power save mode and then back to receivemode is less than the remaining duration of the frame, then theswitching may occur and the receiver may enter the power save mode. Butif the time to switch a sub-system(s) into power save mode and then backto receive mode exceeds the remaining duration of the frame, thenswitching may not occur. The decision to enter the power saving mode mayalso consider signal strength information associated with the wirelesssignal transmitting the incoming frame. Different messages may bereceived on channels having different signal strengths of differentSNRs. It may not be wise to base a power down decision on a messagereceived on a channel whose signal is below a desired threshold becausea more reliable or more readable superseding message may be received ona stronger channel during the time during which the receiver was in apower save mode in response to a message that was likely going to besuperseded.

When the receiver is switched into power save mode, method 400 willsubsequently selectively control a sub-system(s) in the receiver tochange state from the lower power save mode to the higher power receivemode in time (at the estimated end of the remaining frame duration) tomaintain end of frame processing associated with a carrier sensemultiple access collision avoidance (CSMA/CA) protocol with which the802.11 receiver is complying. The sub-system(s) in the receiver alsoneeds to be switched back to receive mode in time to detect the nextincoming frame.

Thus, at 460, method 400 makes a decision concerning whether it is timeto put the receiver back in receive mode. If the determination at 460 isno, then the receiver remains in the power saving mode anddeterminations at 460 continue. The determinations at 460 may be based,for example, on a down-counter in a receive unit (e.g., MAC unit) thatmaintains the remaining time of the frame. If the determination at 460is yes, then at 470, the receiver is put back in receive mode. Placingthe receiver back in receive mode at 470 can include, for example,controlling sub-system(s) in the receiver to change state from the lowerpower save mode to the higher power receive mode.

All time during power save state 450 till entering receive mode state470 the CCA line is signaled busy to comply with the protocol and ensureconsistency of media access timing

At 480, end of frame processing may be performed to maintain acceptableconformance with the controlling protocol. The end of frame processingcan include releasing CCA line to be driven by the conventional receivelogic and NAV/EIFS processing.

FIG. 5 illustrates more details concerning portions of method 400 (FIG.4). Additional detail concerning entering the power save mode at 450 isprovided. Similarly, additional detail concerning entering receive modeat 470 is provided.

Entering the power save mode at 450 can include controlling one or moredifferent sub-systems in the receiver either individually and/orcollectively. Therefore, entering the lower power save mode at 450 caninclude, at 452, controlling a radio frequency unit (RFU) power state.Entering the lower power save mode at 450 can also include, at 454,controlling an analog baseband processing unit (ABB) power state.Entering the lower power save mode at 450 can also include, at 456,controlling a digital baseband processing unit (DBB) power state.Control actions 452, 454, and 456 may be performed serially, inparallel, partially in parallel, and so on.

Different embodiments may include configuring different receive units(e.g., RFU, ABB, DBB) to be able to take on different numbers of states,and for the states to have different power consumptions. In one example,the RFU power states can include, but are not limited to, a first statewhere the RFU consumes less than I_(rf) _(—) _(pd) mA of power, a secondstate where the RFU consumes less than I_(rf) _(—) _(slp) mA of power,and a third state where the RFU consumes more than I_(rf) _(—) _(sb) mAof power. In one example, the ABB power states can include, but are notlimited to, a first state where the ABB consumes less than I_(ab) _(—)_(slp) mA of power, a second state where the ABB consumes less thanI_(ab) _(—) _(sb) mA of power, and a third state where the ABB consumesmore than I_(ab) _(—) _(rx) mA of power. In one example, the DBB powerstates can include, but are not limited to, a first state where the DBBconsumes less than I_(db) _(—) _(slp) mA of power, a second state wherethe DBB consumes less than I_(db) _(—) _(sb) mA of power, and a thirdstate where the DBB consumes more than I_(db) _(—) _(idle) mA of power.

A receiver may be tasked with maintaining a certain signal(s) on a clearchannel assessment line during frame receipt and at other times. If thereceive unit tasked with maintaining that signal is powered down inpower save mode, then another component may be tasked to drive thatsignal onto the line. Therefore, entering power save mode at 450 caninclude, at 458, selectively driving a pre-determined signal onto aclear channel assessment line associated with the 802.11 receiver. Thesignal may be, for example, a BUSY signal.

Entering or returning to the receive mode at 470 can also involve morethan one action. If the receiver powered down a component tasked withdriving a signal onto the CCA line and therefore employed a differentunit (e.g., MAC unit) to provide the CCA signal, then entering thereceive mode at 470 can include, at 472, returning CCA line control tothe originally tasked component.

Entering the receive mode at 470 can also include making a decisionconcerning how to treat the end of frame. The choices can include, at474, selectively triggering network allocation vector (NAV) processing,and, at 476, selectively triggering extended inter frame spacingprocessing. The decision can be configurable but needs to maintain endof frame processing associated with a carrier sense multiple accesscollision avoidance (CSMA/CA) protocol with which the 802.11 receiver iscomplying. Different criteria may be used to decide between NAV/EIFS. Indifferent embodiments, all filtered frames may trigger NAV, all filteredframes may trigger EIFS, some filtered frames may trigger NAV whileothers trigger EIFS, and so on. Signal strength, SNR, frame length,historical channel reliability, and other factors may be considered whendetermining how to configure the NAV/EIFS decision associated withentering receive mode at 470.

The following includes definitions of selected terms employed herein.The definitions include various examples and/or forms of components thatfall within the scope of a term and that may be used for implementation.The examples are not intended to be limiting. Both singular and pluralforms of terms may be within the definitions.

References to “one embodiment”, “an embodiment”, “one example”, “anexample”, and so on, indicate that the embodiment(s) or example(s) sodescribed may include a particular feature, structure, characteristic,property, element, or limitation, but that not every embodiment orexample necessarily includes that particular feature, structure,characteristic, property, element or limitation. Furthermore, repeateduse of the phrase “in one embodiment” does not necessarily refer to thesame embodiment, though it may.

“Logic”, as used herein, includes but is not limited to hardware,firmware, instructions stored on a non-transitory medium or in executionon a machine, and/or combinations of each to perform a function(s) or anaction(s), and/or to cause a function or action from another logic,method, and/or system. Logic may include a software controlledmicroprocessor, a discrete logic (e.g., ASIC), an analog circuit, adigital circuit, a programmed logic device, a memory device containinginstructions, and so on. Logic may include one or more gates,combinations of gates, or other circuit components. Where multiplelogics are described, it may be possible to incorporate the multiplelogics into one physical logic. Similarly, where a single logic isdescribed, it may be possible to distribute that single logic betweenmultiple physical logics. One or more of the components and functionsdescribed herein may be implemented using one or more of the logicelements.

While for purposes of simplicity of explanation, illustratedmethodologies are shown and described as a series of blocks. Themethodologies are not limited by the order of the blocks as some blockscan occur in different orders and/or concurrently with other blocks fromthat shown and described. Moreover, less than all the illustrated blocksmay be used to implement an example methodology. Blocks may be combinedor separated into multiple components. Furthermore, additional and/oralternative methodologies can employ additional, not illustrated blocks.

To the extent that the term “includes” or “including” is employed in thedetailed description or the claims, it is intended to be inclusive in amanner similar to the term “comprising” as that term is interpreted whenemployed as a transitional word in a claim.

While example systems, methods, and so on have been illustrated bydescribing examples, and while the examples have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. It is, of course, not possible to describe every conceivablecombination of components or methodologies for purposes of describingthe systems, methods, and so on described herein. Therefore, thedisclosure is not limited to the specific details, the representativeapparatus, and illustrative examples shown and described. Thus, thisapplication is intended to embrace alterations, modifications, andvariations that fall within the scope of the appended claims.

PREVIOUS DISCLAIMERS RESCINDED

Applicant respectfully informs the Patent Office that the presentdisclosure is a broadening continuation. Applicant rescinds alldisclaimers made during the prosecution of the parent application(s),which may have included statements or amendments that may havedisclaimed scope. Accordingly, the previous disclaimers, and the priorart that it was made to avoid, may need to be and should be re-visited.

What is claimed is:
 1. A method, comprising: detecting an incoming frameat a receive unit operating in a receive frame state; determining thatthe incoming frame is not intended for the receive unit; calculatingexpected power savings for entering an ignore state based, at least inpart, on a switching time and frame duration of the incoming frame; anddetermining to remain in the receive frame state rather than the ignoreframe state when the expected power savings for entering the ignorestate is insufficient, wherein in the receive frame state the incomingframe is received by the receive unit, and wherein when the receive unitis in the ignore frame state the incoming frame is (i) not received or(ii) not decoded by the receive unit.
 2. The method of claim 1, whereinthe switching time comprises an amount of time required to switch thereceive unit from the receive frame state to the ignore frame state andback to the receive frame state.
 3. The method of claim 1, comprising:detecting a subsequent incoming frame at the receive unit operating inthe receive frame state; determining that the subsequent incoming frameis not intended for the receive unit; calculating expected power savingsfor entering the ignore state based, at least in part, on a switchingtime and frame duration of the subsequent incoming frame; determining toenter the ignore frame state when the expected power savings issufficient; selectively controlling the receive unit to enter the ignoreframe state from the receive frame state; and returning the receive unitto the receive frame state in time to perform end of frame processing onthe incoming frame.
 4. The method of claim 1, wherein calculating theexpected power savings includes comparing the frame duration of theincoming frame to a threshold duration.
 5. The method of claim 4,further comprising selectively triggering network allocation vectorupdate processing when the frame duration of the incoming frame isshorter than the threshold duration.
 6. The method of claim 4, furthercomprising selectively triggering extended inter-frame spacingprocessing for the incoming frame when the frame duration of theincoming frame is longer than the threshold duration.
 7. The method ofclaim 1, wherein the returning the receive unit to the receive framestate is also in time to receive a next incoming frame.
 8. The method ofclaim 1, further comprising selecting the end of frame processing fromdifferent types of end of frame processing.
 9. The method of claim 8,wherein the different types of end of frame processing include: treatingthe incoming frame as a frame that has passed a frame check sequencetest and triggering a network allocation vector update processing forthe incoming frame, and treating the incoming frame as a frame that hasfailed the frame check sequence test and triggering extended inter-framespacing processing for the incoming frame.
 10. A receiver apparatus,comprising: a receive unit configured with: a receive frame state,wherein in the receive frame state, the receive unit is configured toreceive an incoming frame and to provide decoded information concerningthe incoming frame; and an ignore frame state, wherein in the ignoreframe state, the receive unit is configured to perform (i) not receivingthe incoming frame, or (ii) not decoding the incoming frame; acontroller configured to: determine that the incoming frame is notintended for the receive unit; calculate expected power savings forentering the ignore state based, at least in part, on a switching timeand frame duration of the incoming frame; determine whether to i) remainin the receive state or ii) enter an ignore frame state based, at leastin part, on the expected power savings; and remain in the receive statewhen the expected power savings is insufficient.
 11. The receiverapparatus of claim 10, wherein the switching time comprises an amount oftime required to switch the receive unit from the receive frame state tothe ignore frame state and back to the receive frame state.
 12. Thereceiver apparatus of claim 10, wherein the controller is configured todrive a pre-determined signal onto a clear channel assessment linecontrolled by the receiver apparatus while the receive unit is in theignore frame state in order to preserve the wireless protocol'sbehavior.
 13. The receiver apparatus of claim 10, wherein the end offrame processing comprises one or more of, triggering a networkallocation vector update, and triggering extended inter-frame spacingprocessing.
 14. The receiver apparatus of claim 13, wherein thecontroller is configured to perform end of frame processing by: treatinga filtered incoming frame as a frame that has passed a frame checksequence (FCS) test by triggering NAV update processing for the filteredincoming frame; treating a filtered incoming frame as a frame that hasfailed an FCS test by triggering EIFS processing for the filteredincoming frame; or selectively triggering NAV update processing when afiltered incoming frame is less than a threshold duration andselectively triggering EIFS processing for a filtered incoming framewhen a filtered incoming frame is longer than the threshold duration.15. The receiver apparatus of claim 10, wherein the controller isconfigured to: detect a subsequent incoming frame at the receive unitoperating in the receive frame state; determine that the subsequentincoming frame is not intended for the receive unit; calculate expectedpower savings for entering the ignore state based, at least in part, ona switching time and frame duration of the subsequent incoming frame;determine to enter the ignore frame state when the expected powersavings is sufficient; selectively control the receive unit to enter theignore frame state from the receive frame state; and return the receiveunit to the receive frame state in time to perform end of frameprocessing on the subsequent incoming frame.
 16. A method forcontrolling power modes for one or more sub-systems in an 802.11receiver, the method comprising: detecting an incoming frame beingreceived at the receiver via a wireless signal; controlling the receiverto receive and decode the incoming frame until frame informationcomprising an intended target for the incoming frame and a frameduration for the incoming frame have been acquired; selectivelycontrolling one or more sub-systems in the receiver to change state froma higher power receive mode to a lower power save mode as a function ofthe frame information and an expected power savings, where the expectedpower savings is computed as a function of the frame duration andswitching times for the one or more sub-systems; and selectivelycontrolling one or more sub-systems in the receiver to change state fromthe lower power save mode to the higher power receive mode in time tomaintain end of frame processing associated with a carrier sensemultiple access collision avoidance (CSMA/CA) protocol with which the802.11 receiver is complying and in time to detect the next incomingframe.
 17. The method of claim 16, comprising controlling the one ormore sub-systems in the receiver to change state from the higher powerreceive mode to the lower power save mode as a function of the frameinformation, the expected power savings, and signal strength informationassociated with the wireless signal transmitting the incoming frame. 18.The method of claim 17, further comprising: upon determining to controlone or more sub-systems in the receiver to change state from the higherpower receive mode to the lower power save mode, selectively driving apre-determined signal onto a clear channel assessment line associatedwith the 802.11 receiver, and maintaining end of frame processingassociated with a carrier sense multiple access collision avoidance(CSMA/CA) protocol with which the 802.11 receiver is complying byselectively triggering either (i) network allocation vector (NAV)processing, or (ii) extended inter frame spacing processing.
 19. Themethod of claim 18, wherein controlling the one or more sub-systems inthe receiver to enter the lower power save mode comprises individuallycontrolling one or more of, a radio frequency unit (RFU) power state, ananalog baseband processing unit (ABB) power state, and a digitalbaseband processing unit (DBB) power state, the RFU power state beingone of: a first state where the RFU consumes less than Irf_pd mA ofpower; a second state where the RFU consumes less than Irf_slp mA ofpower; and a third state where the RFU consumes more than Irf_sb mA ofpower, the ABB power state being one of: a first state where the ABBconsumes less than Iab_slp mA of power; a second state where the ABBconsumes less than Iab_sb mA of power; and a third state where the ABBconsumes more than Iab_rx mA of power, and wherein the DBB power stateis one of: a first state where the DBB consumes less than Idb_slp mA ofpower; a second state where the DBB consumes less than Idb_sb mA ofpower; and a third state where the DBB consumes more than Idb_idle mA ofpower.
 20. The method of claim 16, further comprising selectivelychanging the one or more sub-systems in the wireless receiver from thelower power state to the higher power receive state in time to receive asubsequent incoming frame after the remainder of incoming RF signalsfrom the ignored incoming frame end.